7/09/2009 @ 6:00AM

More Powerful Than Facebook Or Twitter

Every political eruption around the world–the Iranian elections; this week’s riots in the Chinese city of Urumqi–quickly produces news stories about how Internet sites like Facebook and Twitter have become engines of social change. But a technology that is much less glamorous and vastly more ubiquitous deserves the real star billing.

CMOS sensors (“complementary metal oxide semiconductor”) are the cameras-on-a-chip that have become so cheap that they can now be put even in low-end cellphones. Just about everyone in the world by now has a mobile phone, and each one of them has become a witness to history. It’s hard to smuggle around a movie camera, especially when tanks are rolling in. A cellphone, though, slips in a pocket, but its images can beam around the world in minutes. That makes every person on the street a documentary filmmaker.

A CMOS sensor is, in effect, a garden variety silicon computer chip, like a memory chip or a microprocessor, but which can convert photons of light into the electrical ones or zeroes of computer-speak. While digital cameras have been around for decades, until recently they required a complex part known as a charged couple device (CCD) in order to work.

During the 1990s, scientists at NASA’s Jet Propulsion Laboratory and elsewhere got the idea of trying to use generic computer chip technology, known as CMOS, to handle pictures. At first, CMOS-based cameras had extremely low picture quality; they were electrically “noisy,” as engineers say.

But since so many engineers were familiar with CMOS and since basic CMOS manufacturing technology was used in so many places all over the world, a huge R&D infrastructure was in place to quickly make improvements to the devices. Around 2000, they became good enough to start showing up in digital cameras in place of CCDs. By now, CMOS sensors are good enough that they can out-perform CCDs for all but very high-end photography applications, usually for a tiny fraction of the price. (A CMOS sensor in a low-end cellphone costs less than a dollar.)

The story is another victory for Moore’s Law, in which electronics double in capacity every year or so. In five years, says Ken Salsman, director of new technology for Aptima, a CMOS sensor maker in Silicon Valley, the area on a chip required to store a pixel of information has shrunk 10-fold, to a wee 1.5 microns. With advances in manufacturing, more pixels can be stored on the same fingernail-sized sliver of silicon chip. Which is why cameras now start at 8 megapixels, an unimaginable amount just a few years ago but enough to produce high-def video in even low-cost cameras. Some high-end cameras now have 25 megapixels.

Because CMOS sensors are so cheap, they are being designed into everything, the way flashing LED displays were in the ’90s. Laptop covers, for one, and the rear doors of station wagons, giving drivers of some new models a view of what they are reversing into.

Even pills. One of the new fields in radiology is CMOS sensor-enabled capsules that can be swallowed. These capsules can take hundreds or even thousands of pictures as they move through the digestive system. They are then retrieved, and the photos off-loaded for a doctor’s evaluation.

As Salsman says, “There is nothing that isn’t being photographed these days.” Dictators beware.